Sharp Subdivision

The Utah Southern Railroad was built by the Mormons in 1871 to connect Salt Lake City to points south. The line was acquired by the Union Pacific Railroad in 1875. The Utah Southern Railroad name was initially kept as a separate division, but over time the line was moved around and divided among different UP subsidiaries. A significant portion of the line, from Provo to Lynndyl is today known as the Sharp Subdivision. The Union Pacific sold the northern portion of the line to the Utah Transit Authority which today uses the line for light rail.

The first portion of the line was constructed between Salt Lake City and York (south of Santaquin), and acquired by the Union Pacific Railroad (UP) in 1875. Under UP ownership, extensions to the line reached as far south and west as Frisco. In 1881 the railroad was merged into the Utah Central Railway, another UP subsidiary. In 1889 the line was transferred to the Oregon Short Line and Utah Northern Railway, another UP subsidiary.

The line was transferred again during construction of the Los Angeles and Salt Lake Railroad, then partially owned and later fully owned by the Union Pacific. The portion of the former Utah Southern from Lynndyl to Milford was used for the LA&SL main, and remains in use as the primary Southern California - Utah rail trunk today. The remainder of the former Utah Southern became spurs from the LA&SL main. The spurs to Eureka and Frisco were eventually abandoned. The LA&SL and Utah Southern used different routes between Lynndyl and Salt Lake, resulting in duplicate tracks between those two cities. The Utah Southern built tracks were routed to Salt Lake via Leamington Canyon of the Sevier River, passing through Nephi, Santaquin and Provo; the newer LA&SL built tracks were routed farther west in the desert, via Tooele and around the north end of the Oquirrh Mountains. Over time the tracks via Tooele became the preferred route for through traffic and the tracks via Provo became the secondary or local route; however the route via Provo is no longer contiguous. The portion between Provo and Lynndyl is still part of the Union Pacific, and is known as the Sharp Subdivision; the portion through the Salt Lake Valley is no longer part of the Union Pacific network.

...
Wikipedia